Hosiery



Patented June 30,1942

HOSIERY Otto Kress and Charles E. Johnson, Appleton,

Wisconsin Wis., assignors to The Institute of Paper Chemistry, Appleton,Wis,

a corporation of No Drawing. Application-June 23, 1939,

Serial No. 280,704

19 Claims.

The present invention relates to improved hosiery and the method ofmaking the same. More specifically, the present invention is directed tothe replacement of a protein-rubber protective agent upon fibers inwhich the original protective agent has been substantially removed inprocessing.

Silk, wool and other fibers possess inherent undesirable characteristicswith which the hosiery industry have been struggling for years toovercome. Natural silk, for example, has the firmness, strength and bodydesired, but through processing a relatively highpercentage ofprotective gum supplied by nature is removed and silk becomeshygroscopic, pervious to dirt, perspiration and the like, which makesthe fiber susceptible to rapid deterioration. The processing treatmentsmaterially decrease the fiber strength and desired stretch and stockingsmade from the processed fiber have little resistance to snagging and thesubsequent development of runs. Returning a protective agent to fibers,which restores strength, increases stretch, etc. without diminishing thedesirable qualities obtained through processing, has long been a problemof the manufacturers of hosiery.

Many treatments have been attempted in the past but for the most partall have failed to fully accomplish the essentialrequirements. Some ofthe better known treatments have been, dipping the hosiery in solutionsof mineral salts, sizing with starch, glues and waxes, sizing withmineral soaps, etc. In addition, the dipping of hosiery in rubbersolutions has also been su gested. All of these prior treatments havehad objectionable features, such as, the inability to apply evenly anduniformly, the changing of the appearance from that of natural silk toan artificial silk, lack of permanency, tendency to stiffen and harshenthe fabric, danger of rancidity on storing, etc. The rubberized hosieryin particular has been found unsatisfactory due to its sticky and clammyfeel and rapid deteriorationdn storage and under influence of heat andlight. Although the art apparently appreciated the potential value ofrubber gums in the treatment of hosiery, satisfactory compositions'andmethods of application, free from the above noted as well as otherobjections, have not been available up to the present time.

Therefore, the principal object of our invention is to provide,compositions and processes adapted v for use in the manufacture ofimproved hosiery free from thedisadvantages enumerated above.

Further objects will be apparent as soription hereinafter proceeds.

We have discovered that the stable protein emulsion such as described inour co-pending application, Serial No. 76,008, filed April 23, 1936, nowPatent Number 2,172,392, are adapted for use in conjunction with rubbercompositions in the manufacture of improved hosiery. The hosiery treatedwith our novel emulsion comprising finely divided waxy material andfinely divided rubber particles dispersed in an aqueous mediumcontaining a relatively high percentage of protein material and asmaller amount of a the dewater soluble emulsifying agent, are free fromthe disadvantages encountered in treating hosiery with the priorcompositions and particularly the prior rubber containing compositions.For example, hosiery treated with our emulsion as hereinafter describedare not sticky or clammy nor are they subject to deterioration instorage or deterioration under the influence of heat and lightencountered in commercial practice. Hosiery treated in accordance withthe present invention is of greatly increased strength and. stretch, andhighly resistant to the development of runs. No difiiculty isencountered in uniform application of our emulsion to the hosiery, thehosiery being free from rubber, protein and wax spots.

Our emulsions which are prepared by adding liquid or molten waxymaterial and. rubber solution, e. g. latex, to an aqueous alkalinesolution containing a suitable emulsifying agent and a relatively highpercentage of water insoluble, acid precipitable protein and subjectingthe same to agitation, are stable and lend themselves readily tocommercial operation. L1 practice, we have found it desirable to breakor precipitate the emulsion by addition of a small amount of diluteourselves to any particular theory of action, our investigationsindicate that the emulsion when broken by acidic materials forms minuteparticles of wax and rubber coated with a film of insolubilized proteinwhich prevents coalescence of the wax and rubber as well as the proteininto large particles. In other words, the protein and the rubbermaterial and waxy material which latter materials may act as a carrierand an elastic lubricant for the protein, appear to actively cooperateand prevent agglomeration. The protein film also appears to stabilizethe rubber and prevent deterioration during storage as well as protectthe rubber from break-down due to the action of sunlight and heat. Inaddition, the

formation of snags and the acidic material. -While we do not wish tolimit protective film of insolubilized casein-type protein eliminatesthe sticking of the treated stockings to the shaping forms, one of theinherent commercial disadvantages encountered in the manufacture ofrubberized hosiery in accordance with previously suggested processes.

The following example will serve to illustrate the preparation of anemulsion in accordance with our invention.

About 30 pounds of casein (e; g. alpha soya bean protein) is added toabout 13 gallons of water heated to a temperature of about 140-150 F.and the mixture stirred for about minutes until the protein swells.About 1.5 pounds of caustic soda (5 percent based on the weight of thecasein) dissolved in about 1 gallon of water is added to thewater-casein mixture which is maintained at a temperature of about140-150 F. and stirred for about 15 minutes or until the protein iscompletely dispersed or dissolved. To the alkaline casein solution isnext added about 15 pounds of ammonium oleate. To this mixture, which isbeing agitated with a suitable high speed agitator at a speed varyingfrom 600 to 1700 R. P. M., there are added slowly about 90 pounds of amolten waxy material such, for example, as a water-white odorlessparaifin wax (M. Pt. 124 F.) Complete dispersion is-attained in aboutminutes when the melted parafiin or oil no longer remains on the surfaceof the emulsion. Warm water may be added to the proteinwax emulsion soas to obtain the desired fiow characteristics or viscosity. Thisemulsion has a protein to wax ratio of 1:3.

In a separate container about 60 pounds of soya casein are mixed withabout 600 pounds of water at a temperature of about 140 F. To thismixture are next added about 3 pounds of caustic soda (5 percent basedon the weight of the casein) dissolved in a small amount of water. Themixture is stirred for about 15 minutes until the protein is completelydispersed. The protein solution is then cooled to around 100 F. and 1115pounds of rubber latex solution percent rubber i. e. 446 pounds dryrubber) added. The original protein-wax emulsion, the preparation ofwhich is described above, isthen added to the protein-latex dispersionwith proper stirring (mild agitation) and the final emulsion dilutedwith warm water (100 F.) to the desired consistency. For ordinarypractice sufiicient water is added to make the total mixtureapproximately 9160 pounds, which gives a solution consisting of about4.87 percent (e. g. about 5 percent) rubber and about 2.13 percentproteinparafiin-ammonium oleate (e. g. about 2 percent protein-wax). Theratio of protein to paraffin wax in the final emulsion being about 1:1.

It will be understood that the above example is not to be interpreted aslimiting our invention. For example, the soya bean casein for which maybe substituted any water-insoluble, alkali-soluble, acid precipitableprotein such as milk casein, may be added in a single addition insteadof forming the separate protein-wax and proteinrubber dispersions asabove described. In place of the caustic soda employed in the aboveexample, any alkaline protein solubilizing compositions may be usedincluding ammonium and alkali hydroxides and alkaline reacting saltssuch as borax, the sodium carbonates and the tri and di-sodiumphosphates. If an alkaline reacting salt is used in place of thestrongly alkaline sodium hydroxide employed above, it has been foundnecessary to use a slightly higher proportion of solubilizing salt. Forexample, if sodium carbonate (soda ash) is used about 7 percent based onthe weight of the protein has been found sufiicient to give complete anduniform dispersion. In place of the ammonium oleate used in the aboveexample, any suitable emulsifier may be employed such as the sulphonatedoils, Turkey red oil, soluble soaps of any nature, triethanolamine, gumssuch as gum arabic, etc. Our investigations have shown that theproportion of emulsifying agent used should be at least about one-eighthof the amount of waxy material employed, although it is ordinarilypreferred to employ approximately a 1:6 ratio of ammonium oleate to waxymaterial with a protein to waxy material ratio of about 1:1.

It will also be understood by those skilled in the art that in place ofparafiin wax used in the above example, any inert waxy material may besubstituted therefor including lower and higher melting point paraiiinor mineral Waxes including Vaseline, vegetable waxes including carnaubawax, natural waxes, inert fats and oils and the like.

It will likewise .be understood that our invention is not limited to theabove temperatures and proportions of the various ingredients used inour preferred process. For example, our investigations have shown that a1:3 to 3:1 protein to wax ratio and 1:12 to 1:1 protein to rubber ratiomay be employed. In practice, a protein to wax ratio of 1:2 to 2:1 and aprotein to rubber ratio of 1:6 to 3:6 is ordinarily preferred while forsilk hosiery a protein to wax to rubber ratio of about 1:1:5 is, underthe conditions described, preferred. In place of the preferred highspeed stirrer above indicated, any suitable type colloidal mill orhomogenizing equipment may be substituted therefor.

The latex used in the present invention is the ordinary commercialrubber latex. The amount of latex used will naturally vary-With theconcentration of rubber contained in the latex dispersion, sufficientlatex being added to furnish the requisite amount of rubber. Thepreferred type of rubber latex for use in the present invention is onewhich has been prevulcanized, not to the maximum extent but toapproximately two-thirds of the strength which can be developed bymaximum vulcanization. We also prefer to use a rubber latex to which asmall amount of a suitable anti-oxidant has been added, which tends toprevent the oxidation of the fine rubber film. Latex including thepartially vulcanized and stabilized rubber latex dispersions areavailable on the open market.

The emulsion, prepared for example as above described, may be applied inany suitable manner to the fibers either prior or subsequent toknitting. In practice, we have found it desirable to apply the emulsionto the knitted hose just after the completion of the dyeing operationwhen the fibers are moist. In our preferred process the moist stockingsor socks are placed in a suitable container such as a rotary dye machineand are soaked in the protein-rubber-wax emulsion contained therein forabout 20 to 40 minutes. The hose are then placed in an extractorcentrifuge for a period of about one minute to remove excess emulsion.(The length of time depending on the degree of extraction desired.) Thehose are next placed in another vat or container and treated for about510 minutes with a dilute acidic solution such as a one-eighth tothree-eighths percent iron-free paper makers emulsion bath may beadjusted to the desired concentration by addition of waterfor byaddition of fresh emulsion. In practice, we have found a concentrationof about 7 percent solid content (i. e. protein-rubber-wax) to bepreferred, although lower (e. g. 3-5%) or higher (e. g. 911%)concentrations may be used, if desired. The use of low concentrations,e. g. 1 or 2 percent, yields corresponding results of less value due tothe relatively small amount of emulsion retained by the fiber, while theuse of high'concentrations, e. g. over 12 percent, increases danger ofmechanical troubles, such as spotting of the finished hose, etc. Ourinvestigations show that the preferred concentration of the rubber inthe treating emulsion should be about 3 percent to '7 percent. Theoptimum concentrations which depend upon results desired, type ofhosiery to be treated, etc. may be ascertained by experimental tests.

It will be understood that our invention is not limited to the abovedescribed method of emulsion application. Any suitable manner ofincorporating the emulsion into the hosiery so as to thoroughlyimpregnate the threads or fibers may be employed. The times given in theabove example are only illustrative and may be varied as desired to suitthe weight of the hosiery treated etc. It will also be understood bythose skilled in the art that our invention is not limited to the use ofthe above described acidic agent. Any suitable acidic agent or acidreacting salt, such as aluminum sulphate, that will break the alkalineprotein-rubber-wax emulsion, may be used. The formaldehyde present inthe acidic solution aids in insolubilizing the casein-type protein. Theacidic reagents or protein insolubilizing agents employed should be suchas do not deleteriously affect the colors of-the dyed fibers.

Our invention is adaptable for all types of hosiery including silk,wool, and cotton hose as well as hosiery made from syntheticcompositions such as rayon, etc. However, as indicated above, ourinvention is particularly adaptable for use in the manufacture ofimproved silk hose. Hosiery treated in accordance with the presentinvention is rendered non-hygroscopic and impervious to dirt, etc. Ofgreat importance, hosiery treated in accordancewith the presentinvention is of increased strength and stretch. The treated hose alsohas an extremely high resistance to snagging and the development ofruns. Experiments run on age tests using both the standard oxygen bomband oven-aging equipment indicate that hose treated-with our novelemulsion suffer no deterioration of the rubber film for a period of atleast two years. Mill runs have shown the protein-rubber-wax emulsion ofthe present invention to be stable under pumping, agitation and otherconditions encountered during actual commercial operation. No mechanicaldimculties are encountered either through the spotting of the goods as aresult of uneven application 'or through the sticking of the hose whilebeing dried in the customary manner on the so-called boarding machines.

The emulsion of the present invention examined under the ultramicroscopeshows a splendid Brownian movement, and when precipitated with alum oracid is free from agglomeration into large particles of any-of theprecipitated ma-' terials. This characteristic is of the essence in thetreatment of hosiery fibers. Ordinary rubber latex dispersions on theother-hand due to the agglomeration of rubber particles has been foundunsatisfactory for use in the hosiery art.

One of the greatest advantages of our invention was in the discoverythat our novel emulsion made the fibers highly flexible and elastic andgave the stockings the desired increase in stretch.

, In the hosiery art this property is also of the essence.

. Although we have illustrated our invention with a preferred processand specified ingredients, it willbe understood that our invention isnot limited thereto. For example, our emulsion may be applied in someinstances without subsequent treatment with acidic material, althoughthe precipitations with alum or the like is preferred. Likewise,although we prefer to applyv the emulsion to the hose and then treatwith an acidic solution the reverse, i. e. initial treatment with alumand subsequent application of the emulsion, may be followed, if desired.

The treated hose of the present invention is water resistant and retainsthe desired splashproof properties of hose treated in accordance withour related co-pending application for Proteinized hosiery, Serial No.181,294, filed December 23, 1937, now Patent Number 2,192,919. Thischaracteristic is not obtainable using ordinary rubber-compositions,including latex, which in addition, are relatively unstable. Theimproved hosiery of the present invention is dependent upon thewax-rubber combination as well as the specific protein, all of which areessential ingredients of the treating emulsion.

All modifications coming within the spirit and scope of our inventionare intended to be covered by the following claims.

.We claim:

1. The step in the method of treating hosiery which comprises applyingto hosiery an emulsion consisting of an aqueous dispersion containing awater-insoluble, acid precipitable protein, a rubber latex, particles ofinert waxy material and a water-soluble emulsifying agent, the ratio ofprotein to waxy material being about 1:3 to 3:1 and the ratio of proteinto. rubber being about 1:12 to 1:1, so that the protein surrounds andforms a film about the rubber and waxy material particles preventingagglomeration of the protein, rubber and waxy material when the emulsionis broken by addition of acidic material. v

2. The step in the method of treating hosiery emulsion consistingessentially of an aqueous alkaline dispersion of an alkali-soluble,waterinsoluble, acid precipitable protein, a rubber latex, particles ofinert waxy material and an emulsifying agent, and breaking the emulsioncontained in the hosiery by treating the same with a dilute acidicmaterial, the ratio of protein to waxy material being about 1:3 to 3:1and the alkaline dispersion of casein,

ratio of protein to rubber being about 1:12 to 1:1 so that the proteinsurrounds and forms a film about the rubber and waxy material particlespreventing agglomeration of the protein, rubber and-waxy material whenthe emulsion is broken upon addition of the acidic material.

4. The steps in the method of treating hosiery which comprisesimpregnating hosiery with a dispersion containing as its essentialingredients an aqueous alkaline dispersion of a casein protein, astabilized rubber latex, a mineral wax and a water-soluble emulsifyingagent, and breaking the dispersion contained in the hosiery by treatingthe hosiery with an acidic material, the ratio of protein to wax being1:3 to 3:1 and the ratio of protein to rubber being about 1:12 to 1:1.

5. The steps in the method of treating hosiery which comprisesimpregnating hosiery with an emulsion containing an aqueous alkalinedispersion of soya bean casein, a partially pre-vulcanized rubberlatex,a paraflin wax and a soap emulsifying agent, and breaking theemulsion contained in the hosiery by treating the hosiery with anaqueous aluminum sulphate solution, the ratio of casein to wax beingabout 1:1 and said emulsion containing about 2 percent of caseinwax andapproximately 5 percent rubber.

6. The method of precipitating rubber material upon silk fibersparticularly adapted for use in the hosiery art, which comprisestreating the fibers with an emulsion consisting of anaqueous alkalinedispersion of a water-insoluble casein, a rubber latex, an inert waxymaterial and an emulsifying retained by the fibers by treating thefibers with a dilute aqueous solution of alum. the ratio of casein towaxy material being about 1:2 to 2:1 and said emulsion containing about5 to 9 percent casein-rubber-wax, the percentage of rubber in saidemulsion being about 3 to 7- percent.

'7. The method of precipitating rubber material upon hosiery fiberswhich comprises treating the fibers with an emulsion consisting of anaqueous alkaline dispersion of soya bean protein, a rubber latex, aparaffin wax having a melting point of about 124 F., and a soapemulsifying agent, and breaking theemulsion by treating the fibers withan aqueous paper makers alum solution, the ratio of protein to parafiinand rubber being such as to prevent agglomeration of the protein, waxand rubber into large particles upon treatment with the alum solution.

mineral wax and an emulsifying agent, removto rubber being about 1:5.

9. The steps in the method of treating silk hosiery which comprisesimpregnating the hosiery with an emulsion consisting of an aqueousalkali dispersion of soya bean casein, a pre-vulcanized rubber latex, a'paraflln wax and ammonium'oleate, removing excess emulsion from thehosiery and breaking the emulsion remaining in the hosiery byimpregnating the hosiery! with a dilute aqueous aluminum sulphatesolution containing a small amount offormaldehyde,

agent, and breaking the emulsion the ratio of casein to rubber beingabout 1:5, said emulsion containing about 5 percent rubber.

10. The method of precipitating rubber material upon silk hosiery, whichcomprises treating the hosiery with an emulsion consisting of an aqueouscaustic soda dispersion of alpha soya bean protein, a rubber latex inwhich rubber has been partially vulcanized and stabilized by theaddition of a small amount of a rubber antioxidant, parafiin wax andammonium oleate, and breaking the emulsion retained by the hosiery bytreating the same with a dilute aqueous formaldehyde solution of papermakers alum, the ratio of protein to ratio of protein to rubberbeingabout 1:5, and the total protein-rubber-wax content in said emulsionbeing approximately 7 percent.

11. As a new article of manufacture, hosiery having incorporatedtherewith a composition made up of minute particles of rubber, and inertwaxy material surrounded by a film of a waterinsoluble, acidprecipitable protein, the ratio of protein-to waxy material being about1:3 to 3 :1 and the ratio of protein to rubber being about 1:12 to 1:1.

12. As a new article of manufacture, hosiery having incorporatedtherewith a composition consisting essentially of minute particles ofrubber and mineral wax surrounded by a film of insolubilized casein, theratio of casein to wax being about 1:1 and the ratio of casein to rubberbeing about 1:5.

13. As a new article of manufacture, hosiery fibers having precipitatedthereon a composition consisting essentially of minute particles ofparalfin wax and rubber surrounded by a film of soya bean protein, theratio of protein to wax being about 1:2 to 2:1 and the ratio of proteinto rubber being about 1:5.

14. As a new article of manufacture, silk hosiery having precipitated onthe fibers thereof, a composition made up of minute particles ofparaffin wax and partially vulcanized rubber surrounded by a film ofinsolubilized soya bean casein, the ratio of casein to wax to rubberbeing about 1:1:5.

15. A silk stocking having precipitated on the threads thereof acomposition consisting of minute particles of a lubricating inert waxymaterial and' minute particles of an elastic antioxidant stabilizedpartially vulcanized latex rubber, said particles being coated with apaper makers alum-formaldehyde insolubilized alpha soya bean protein.

16. Hosiery having incorporated therewith the paper makers alumprecipitate of an emulsion consisting of an aqueous alkaline dispersioncomprising a water-insoluble acid-precipitable protein, a rubber latex,particles of inert waxy material and an emulsifying agent, the ratio ofprotein to waxy material being about 1:2 to 2:1 and the ratio of proteinto rubber being about 1:6 to 3:6.

17. Hosiery having incorporated therewith an aluminum sulphateprecipitate of an emulsion consisting essentially of an aqueous alkalinedispersion ,of a water-insoluble casein protein, a stabilized rubberlatex, particles of mineral wax and a soap emulsifying agent, the ratioof casein to rubber to wax being such as to prevent agglomeration andformation of large particles.

.18. Silk hosiery having incorporated therewith a paper makersalum-formaldehyde precipitate.

. of an emulsion consisting of an aqueous alkali the ratio of casein towax being about 1:1 and dispersion of soya bean protein, a partiallyvulparaflin being about 1:1, the

canized rubber latex, particles of parafl'in wax and ammonium oleate,the ratio of protein to wax being about 1:1 and the ratio of protein torubber being about 1:5, said emulsion containing about 5 percent rubber.

' 19. Silk hosiery having precipitated on the fibers thereof an acidicprecipitate of a rubber latex emulsion consisting of an aqueous alkalinedispersion of a'water-insoluble, "acid-precipitable protein, particlesof an inert waxy material and an emulsifying agent, suflicient proteinbeing presentto prevent agglomeration and formation of large particleswhen the emulsion is broken CERTIFICATE OF CORRECTION.

Patent No. 2,288,561. June 30, 19m.

' OTTO 'KRESS, ET AL,

It is herebyeertified tint error appears iii the printed specificationof the above numbered patent requiring c0 rrection as follows: Page 5,second column, lineflhb, claim 1, after the word "aqueous" insert"alkaline";

and that the said Letters Patent should beread with this correctionthereirithat the same may conform to the record-of the case iri thePatent Office.

signed and. sealed this tum day of August, A. D. 191;.2.

Henry Veh Arsdale,- (Seal) Acting Commissioner of Patents.

